This invention is directed to nocturnal penile tumescence and rigidity monitoring devices and more particularly to a novel flexible, adjustable, disposable, sensing device and method for monitoring penile tumescence and rigidity.
Nocturnal penile tumescence monitoring has become widely used as a diagnostic procedure for determining whether male impotency is psychogenic or organic. A known device for monitoring penile tumescence, as shown in PCT Publication No. W083/03748, includes strain gauges placed in two penile locations to measure increases and decreases in penile tumescence during nocturnal periods.
A recent article entitled "Development of a Penile Rigidity Indicator and New Concepts in the Quantification of Rigidity" by K. M. Desai et al. in the 1988 British Journal of Urology, pp. 254-60, states that the measurement of girth change alone "is prone to diagnostic misinterpretation since increase in penile circumference is not synonomous with rigidity and significant expansion may occur in the absence of a rigid erection."
Thus the monitoring of penile rigidity as well as tumescence is believed helpful in diagnosing male impotency, since penile tumescence without the requisite rigidity will usually not suffice to effect vaginal penetration.
The aforementioned British Journal of Urology article describes a PERIN device (Penile Rigidity Indicator) capable of monitoring rigidity as well as tumescence, citing an apparently unpublished Great Britain Patent No. 82708215. The PERIN device for measuring penile rigidity and tumescence, as disclosed in the foregoing article, includes a sensor that is retained around the penis using a foam strap fastened with Velcro tape. The foam strap maintains a retaining force at a relatively constant level during various phases of erection.
The PERIN sensor consists of a contoured platform with a protruding stylus. The stylus is mounted on a pivoted lever which acts on a spring beam having resistance strain gauges that indicate an applied force. The sensor includes tongs made of pliable plastic material which incorporate a metal strain gauge for simultaneous girth monitoring. The sensor stylus makes direct contact with the tunica albuginea of the penis.
The pliable plastic tongs permit fitting of the sensor onto different subjects and the device is thus reusable, with the sensor being permanently wired to a data conversion device.
Consequently there is a need to sanitize the PERIN device each time it is used. In addition, the pliable plastic tongs of the PERIN device are not easily adaptable to exactly conform to a penile contour. Thus the PERIN monitoring system may be subject to calibration errors.
Another known device for measuring penile tumescence and rigidity is disclosed in U.S. Pat. 4,515,166. The disclosed device employs a cable that forms a noose-like fitting around the penis, and a sprocket arrangement that may also be subject to calibration errors. The disclosed system for measuring penile rigidity includes a torque motor on an elongated member that encircles the penis. The use of cable displacement as a measure of compressibility or rigidity is a relatively cumbersome arrangement that can be discomforting to the user.
It is thus desirable to provide a sensing device for monitoring penile tumescence and rigidity which can be easily installed on a patent, conforms exactly to a penile contour, is comfortable to use during nocturnal periods, and is disposable after use.